Air pollution

This website tells the causes of air pollution.
http://healthandenergy.com/air_pollution_causes.htm

This wikipedia website has tons of information about air pollution.
http://en.wikipedia.org/wiki/Air_pollution

This website has the effects of air pollution on humans and animals.
http://www.hc-sc.gc.ca/ewh-semt/air/out-ext/effe/health_effects-effets_sante-eng.php